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Version: 1.3 Status: Approved A new version will be created automatically if this content is modified.
Alan Williams, Commonwealth Scientific and Industrial Research Organisation, Hobart, Australia
Thomas Schlacher, University of the Sunshine Coast, Australia
Franziska Althaus,Commonwealth Scientific and Industrial Research Organisation, Hobart, Australia
Ben Gilby, University of the Sunshine Coast, Australia
Andrew Olds, University of the Sunshine Coast, Australia
Rudy Kloser, Commonwealth Scientific and Industrial Research Organisation, Canberra, Australia
Environmental heterogeneity promotes fauna diversity in submarine canyons
Submarine canyons may support high diversity and abundance of benthic megafauna relative to other seabed areas, and are frequently regarded as priority features for marine conservation planning, e.g.  in the design of Australia’s deepwater reserve system.  However, not all canyons provide suitable habitats for benthic fauna, and it is not known how diversity of benthic megafauna is generally related to properties of canyon environments.  Here we test whether there is enhancement of faunal diversity by habitat heterogeneity in canyons at local scales.  We analysed data from 63 video transects taken in 21 canyons off Australia over a depth range of 72-1299 m.  Analysis was based on approximately 172,000 individual images scored for properties of fauna, substratum type and seabed geomorphology, together with metrics for seabed slope and hardness derived from multi-beam acoustic data.  We found the combined effect of depth range (primarily) and variance in seafloor properties (mostly substrate type) drive patterns in fauna diversity.  Further, there was a strong effect of local seabed heterogeneity on faunal diversity matched at the same scale. These local effects are, hypothetically, modified and re-shaped by a) processes acting at the scale of whole canyons (e.g. size, upwelling intensity), b) seascape effects (e.g. connectivity) and c) bottom fishing disturbance. The relative roles of these larger-scale drivers and their interactions remain to be tested.
Theme 3: Biological patterns in submarine canyons: role of scale and heterogeneity
Oral Presentation
benthic megafauna, habitat, heterogeneity, Australia